• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.39-48
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• 2006

In this paper, we analyze the spectral efficiency of multicarrier-code division multiple access (MC-CDMA) scheme. First, we derive a generalized formula for the spectral efficiency according to the number of subcarriers involved in, code division multiplexing and the number of codes used (i.e., loading factor), under a given set of channel coefficients. Also, we derive a generalized formula for spectral efficiency of various reduced-complexity systems that divide the full sets of subcarriers into several groups of subcarriers for code division multiplexing. Then, through these derivations, we establish an inter-relationship between the frequency selectivity and diversity order according to the number of multipaths. From the results, we choose the smallest code length while maximizing the diversity effect, provide an optimum subcarrier allocation strategy, and finally suggest a system structure for capacity-maximizing under the smallest code length. Through numerical analyses under simulated environments, we analyze the properties of spectral efficiency of various systems with reduced complexity and choose a major contributing factors to system design and a better system design methodology. Finally, we compare the spectral efficiency of the MC-CDMA scheme and orthogonal frequency division multiplexing (OFDM) scheme to make a relationship between both schemes.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.337-344
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• 2007

We have investigated the relationship between food allergen sensitization and allergic disease in 74 child (male 47, female 27) patients from 0 to 14 years of age diagnosed with allergic disease. The age distribution for the study was: newborn to 3 years old, 34 children; 4 to 6 years old, 24 children; 7 to 9 years old, 8 children and above 10 years old, 8 children. Of the 74 children, 10 children were allergic to 3 of the 21 types of foods tested, 21 children were allergic to 4 types and 15 children were allergic to 5 types. The results of specific IgE tests for class 2 (0.070-3.49 IV/mL, IgE density in serum) showed that 29 children were allergic to milk, 28 children to bean, 21 children to cheese, 7 children to egg, and 18 children to pork, while over class 2, 20 children were allergic to bean, 17 children to milk, 24 children to cheese, 20 children to egg, and 21 children to pork. A questionnaire was used to survey family allergy history and diet patterns for 40 child (male 22, female 18) patients with allergic disease. The frequencies of a family history of allergy were 45.5% for males and 50.0% for females. The allergic diseases included atopic dermatitis: 26.0%, atopic nasitis: 10.5%, atopic dermatitis + atopic nasitis : 31.5%, hives: 21.0%, and asthma: 10.5%. Children on diets of mixed breast feeding and infant formula were more allergic than those on either breast feeding or infant formula feeding. Eliminated allergenic foods were egg + milk: 12.5%, egg: 10.0%, and milk 2.5%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.92-99
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• 2021

In the case of precise safety inspection and precise safety diagnosis of a building, a condition evaluation must be conducted to determine the safety grade. Since 2004, an evaluation method using fuzzy theory has been introduced for quantitative condition evaluation,and the relationship and importance of reinforced concrete members using fuzzy theory have been applied. Generally, fuzzy theory is a method used to deal with ambiguous expressions with unclear correlations, but at the time of development, it seems that it was developed by applying fuzzy theory as an alternative in a situation where inspection and diagnosis result data were insufficient. Therefore, it is necessary to verify the relationship and importance of evaluation items derived based on the current fuzzy theory using actual inspection and diagnosis result data.In this study, the correlation between the evaluation items was derived by using the results of 19 precision safety inspections and 9 precision safety inspections and the performance score function formula, and using this, a reasonable durability score calculation formula of the member was presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.14-34
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• 2023

The purpose of this study was to calculate the appropriate yellow-signal time for intersections, to find out the relationship between the approach speed and intersection width when calculating the time, and to secure safety by minimizing conflicts and dilemma sections in intersections that change according to the signal operation. For this purpose, 6,824 data points from 5 intersections were collected and analyzed. The main results of the study are as follows. First, the approach speed of individual vehicles in different lanes was analyzed, and the width of an intersection was defined by considering the conflict in each direction. Second, we developed a multiple regression model based on the approach speed and conflict points, which compensated for the problems of an existing formula. Third, a standard table is presented for applying the appropriate yellow-signal time according to the approach speed and intersection width based on a development formula. A method is also presented to determine the safety of the length of the dilemma according to the change in the yellow-light time by presenting a calculation table that can cross-analyze the yellow-signal time and a dilemma section using the relationship.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.239-247
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• 2015

Recently, various research studies on frontal collision and rear-ender which occur more frequently compared to others are underway as the public interest on them is growing. This study analyzes scientifically the relationship between effective impact speed and injury incidence for vehicle crash accident reconstruction and presents a relevant model formula. Because real vehicle experiments have certain limitations such as possible injuries, this study efforts to collect and analyze as many materials as possible to substitute real vehicle experiments, including data from various collision tests and human experiments. As a result, this study present a threshold in which head-on collisions and rear impacts do not cause injuries under 7 km/h of effective impact speed, and suggests a model formula showing that injury extent is linearly proportional to effective impact speed through collision speed and amount of plastic deformation. In conclusion, a model formula for estimating effective impact speed and injury incidence newly proposed in this study is expected to be used as a minimum standard of judgment in disputes on the injury extent of passenger in head-on collisions and rear impacts. Furthermore its availability in terms of technological analysis in legal arguments is expected to be very high if this study will be enhanced by referring to scientific analyses of various real accidents so as to apply it in various types of collision accidents.

• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.3-11
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• 2005

The purpose of this study was to examine the long term effects of breast feeding on growth, bone development and nutrient intakes in preschool children. Subjects were 62 preschool children. Anthropometric characteristics and bone mineral density of carpus were measured using DEXA. The questionnaire was composed of health status, life style, dietary behaviors, and dietary intakes and was completed by the children's mothers. The average age of the boys was 62.4 months and that of the girls was 62.1 months. Average birth height and weight of the subjects was 50.9 cm and 3.4 kg for boys and 50.3 cm and 3.3 kg for girls, respectively. The average height, weight, $\%$ body fat, and obesity index were 111.7 cm, 19.6 kg, $15.0\%$, $-2.1\%$ in boys and 109.4 em, 18.7 kg, $17.5\%$, $0.2\%$ in girls, respectively. Forty children were fed colostrum, 21 were fed breast milk, 29 were fed formula, and 12 were fed mixed milk. There was no significant difference in growth status between children who were fed colostrum and those who were not. Children who had mixed feedings were significantly taller than those who did not (p <0.001), and children who had colostrum had significantly higher bone mineral density than those who did not ($0.25 \pm 0.04 g/ cm^2$ vs. $0.23 \pm 0.04 g/cm^2$, p < 0.05). However, the different feeding methods did not show any difference in bone mineral density. Except vitamin $B_6$, folic acid and vitamin E, vitamin, mineral and calorie intakes did not meet the Korean RDAs. Calcium intake was especially lower than recommendations by as much as $62\%$ and $70\%$ in boys and girls, respectively. There was no significant difference in nutrient intakes between children who had colostrum and those who did not. However, children who were formula consumed significantly more animal fat than those who did not (p < 0.05). Neonatal feeding and breast or formula feeding seems to associate with height, bone mineral density and animal fat intakes in preschool children, based on the results of this study. A longitudinal study is needed to clarify this relationship.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.403-415
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• 1999

This study is to derive the rainfall intensity formula based on the representative probability distribution in Korea. The 11 probability distributions which has been widely used in hydrologic frequency analysis are applied to the annual maximum rainfall. The parameters of each probability distribution are estimated by method of moments, maximum likelihood method and method of probability weighted moments. Four tests such as $x^2$-test, Kolmogorv-Smirnov test, difference test and modified difference test are used to determine the goodness of fit of the distributions. The homogeneous tests (Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance of nonparametric test) are applied to find the stations with rainfall homogeneity. The results of homogeneous tests show that there is no representative appropriate distribution for the whole duration in Korea. The whole region could be divided into five zones for 12-durations. The representative probability distribution of each divided zone for 12-durations was determined. The GEV distribution for I,II,V zones and the 3-parameter Weibull distribution for III,IV zones were determined as the representative probability distribution. The rainfall were obtained from representative probability distribution for the selected return periods. Rainfall intensity formula was determined by linearization technique for the rainfall.

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.1
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• pp.1011-1034
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• 1966

This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

• Journal of Korean Medical classics
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• v.21 no.1
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• pp.111-122
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• 2008

At the book I of "The Golden Mirror of Medicine[醫宗金鑑] The Elimination and Supplement about Famous Prescription Comments[刪補名醫方論]", 22 prescriptions are recorded. At the first part of the book, it mainly described about the prescriptions of invigorating Gi[補氣], which is followed by the prescriptions on enriching blood and nourishing vital essence fluid[補陰血], and the prescriptions on strengthening Gihyeol[補氣血] and tranquilization[安神] are described at the last part of the book. At the current review, the 8 prescriptions of strengthening Gihyeol[補氣血] and tranquilization[安神] of the last part of the book I will be translated, and compared with the similar related comments in the book of "The Famous Prescription Comments on Ancient and Modern Times[古今名醫方論]" to review about the characteristics of formula, prescriptions notes and the relationship of these contents. In terms of formula, the order of prescriptions to strengthen Gihyeol[補氣血] could be listed from the indirectly strengthening prescriptions to the directly strengthening prescriptions. In addition, the list of prescriptions will be sequenced by following the order of weak strengthening prescriptions to the strong strengthening prescriptions. The order of tranquilization prescription must be ordered for the symptoms showing mild psychological symptoms to severe symptoms in terms of severity of symptom, and will be ordered from the prescriptions highly dependent on invigorating Gi[補氣] to the prescriptionless dependent on invigorating Gi[補氣]. In the way of controlling Premier Fire[相火], these prescriptions are ordered from the prescriptions that use indirect methods to the prescriptions that use direct methods Characteristics of the prescription notes could be mentioned that the herbs of invigorating Gi(補氣) is pivotal in strengthening Gihyeol[補氣血] and the sour flavor and pungent flavor acted as negative and positive[陰陽的] when sour flavor and pungent flavor are used to enrich liver, and that sweet flavor could easily indigested to cause abdominal distension. When comparing with the content of "The Famous Prescription Comments on Ancient and Modern Times[古今名醫方論]", it mostly adopted the content as it is, but differentiation of the formula and addition of 2 new prescriptions with their explanation in the middle of the book could be considered to be creative aspect that helped the convenience of readers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.57-65
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• 2015

The purpose of this study was to examine dietary habits and nutrient intakes according to feeding method during infant period in elementary school students. Subjects were 1,251 elementary school students. Subjects were divided into three groups, breast-fed group (N=508), formula-fed group (N=397), and mixed group (N=346), according to feeding method during infant period. The questionnaire was composed of general characteristics, dietary conditions during infant period, dietary behaviors, and dietary intakes and was completed by children and children's parents. Average age, height, weight, and body mass index were 11.6 years, 139.0 cm, 34.6 kg, and $17.8kg/m^2$, respectively. The formula-fed group showed a smaller proportion of subjects with colostrum feeding (P<0.001) compared to the breast-fed and mixed groups. Frequency of eating snacks was significantly higher in the mixed group than in other groups (P<0.05). There was no significant difference in dietary habit total score and nutrient intakes according to feeding method during infant period. Feeding method in during infant period was associated with dietary habits (milk and vegetable intake habits) up to growth period of elementary school. A longitudinal and systematic study is needed to clarify this relationship.